Vancokem Mechanism of Action

Therapeutic Classification: Antibacterial agents.
Pharmacology: Pharmacodynamics: Vancomycin is a biological material, described as a tricyclic glycopeptide obtained from cultures of Nocardia orientalis (Streptomyces orientalis). Vancomycin is present as the hydrochloride salt for parenteral administration. The drug is not absorbed from the gastrointestinal tract, and an aqueous solution of the product can be administered orally in the treatment of pseudomembranous colitis.
Vancomycin is a bactericidal antibiotic and appears to bind to the bacterial cell wall causing blockage of glycopeptide polymerisation. This effect produces immediate inhibition of cell wall synthesis and secondary damage to the cytoplasmic membrane. It is active against many gram-positive organisms including Staphylococci, group A beta haemolytic Streptococci, Streptococcus pneumoniae, Enterococci, Corynebacterium and Clostridium species. It does not demonstrate clinical efficacy against gram-negative bacteria, fungi or yeasts, and hence the product literature only indicates use in severe infections caused by gram-positive organisms.
Pharmacokinetics: Vancomycin is poorly absorbed by mouth. An intravenous dose of 1 g produces serum levels averaging 25 microgram per mL after two hours in patients with normal renal function. Serum levels are higher in patients with renal impairment and toxicity may result. Vancomycin is excreted unchanged in the urine, at least 80% is excreted in the first 24 hours. It has a half-life of about 6 hours in patients with normal renal function. Vancomycin readily diffuses into pleural, pericardial, ascitic and synovial fluids. It does not diffuse into cerebrospinal fluid with normal meninges, but therapeutic concentrations may be reached in patients with acute meningitis. Vancomycin is active against many gram-positive organisms including Clostridium difficile. Gram-negative bacteria, mycobacteria and fungi are highly resistant. Many strains of gram-positive bacteria are sensitive in vitro to Vancomycin concentrations of 0.5 to 5 microgram/mL, but a few Staphylococcus aureus strains require 10-20 microgram/mL for inhibition.